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Odor from Crawl Space

What kind of smell does your fogger spray have. I want to try it but do not want anything that will be too strong in case the smell leaks into the living area. Thanks for the suggestion.

G

There is almost no smell at all from the product. It's a compound similar to baking soda. If I had to describe it I say there's almost, maybe, a temporary sort of "chalky" odor. But it goes away as soon as it dries

For about $20 for a gallon, and I think it was $25 to rent the fogger, I don't see how you can lose. At the least, it will deodorize the stale air down there, and it will coat every surface to cover any leftover mold spores. It does not leave much of a "coating", not slimy or anything, but supposedly encapsulates mold, killing it and preventing it from shooting out spores. I say supposedly because that's their advertisement, but I know it helped in my crawl. If this helps, you can probably assume if you plug in a dehumidifier down there and keep it dry, you may have completely solved your puzzle. If it doesn't actually solve your problem, it's not related to mold or mildew, but it will still help deodorize any bad odor to some extent.

http://www.concrobium.com/ <---check it out. My Depot had it in the paint chemical area, but if your's doesn't have it you can order online. Just google it because I don't think they sell directly.

Odor from Crawl Space

Another update: My installer fogged the crawl space with the Concrobium to no avail. The smell inside my house is a minimum thanks to the air sealing in the crawl. However, the earthy, cat urine, plastic smell (depends on who the smeller is) remains. I think I can officially rule out any issues with the HVAC. I think I can also conclude that the smell is not caused by any mold in the dying stage. It has been 3 months since the remediation, plus as Pucks stated, the Concrobium should have ridded the crawl of smell if the smell was from mold. I have to revert back to off gassing from some material installed in the crawl while sealing it. At this point, I have two options. 1. Give it more time to go away on its own (we are currently using two crawl vent fans and a dehumidifier) or 2. Rip out the materials starting with the vapor barrier and see if the smell leaves with the materials.

Odor from Crawl Space

Quote:

Originally Posted by G Ollis

Another update: My installer fogged the crawl space with the Concrobium to no avail. The smell inside my house is a minimum thanks to the air sealing in the crawl. However, the earthy, cat urine, plastic smell (depends on who the smeller is) remains. I think I can officially rule out any issues with the HVAC. I think I can also conclude that the smell is not caused by any mold in the dying stage. It has been 3 months since the remediation, plus as Pucks stated, the Concrobium should have ridded the crawl of smell if the smell was from mold. I have to revert back to off gassing from some material installed in the crawl while sealing it. At this point, I have two options. 1. Give it more time to go away on its own (we are currently using two crawl vent fans and a dehumidifier) or 2. Rip out the materials starting with the vapor barrier and see if the smell leaves with the materials.

As always, I apprecieate any comments or suggestions.

G Ollis

Gary,

Refresh me:

1. Do you still have crawl air deliberately mixing with indoor air via your HVAC system? I assume not, just checking.

2. What was done to the underside of your floor to stop the smell from getting up into the house? A single coat of a stain blocker won't do the job. If you apply multiple coats, till the surfaces are "as smooth as a baby's bottom" then you will block most smells. At least that's what I had to do to stop a mold smell that was actually on top of my old kitchen floor - before putting new laminate down.

Odor from Crawl Space

Quote:

Originally Posted by G Ollis

Another update: My installer fogged the crawl space with the Concrobium to no avail. The smell inside my house is a minimum thanks to the air sealing in the crawl. However, the earthy, cat urine, plastic smell (depends on who the smeller is) remains. I think I can officially rule out any issues with the HVAC. I think I can also conclude that the smell is not caused by any mold in the dying stage. It has been 3 months since the remediation, plus as Pucks stated, the Concrobium should have ridded the crawl of smell if the smell was from mold. I have to revert back to off gassing from some material installed in the crawl while sealing it. At this point, I have two options. 1. Give it more time to go away on its own (we are currently using two crawl vent fans and a dehumidifier) or 2. Rip out the materials starting with the vapor barrier and see if the smell leaves with the materials.

As always, I apprecieate any comments or suggestions.

G Ollis

G-

I was hoping to at least hear that if the Concrobium didn't work, it would at least settle down the odor enough for you to track it down to a specific area or specific item.

Can you refresh me as to what you have for a floor? Are you on soil or cement? Used a plastic liner for vapor barrier? What kind of adhesives have been used down there?

Reason I'm asking is, I think you said you're on soil floor with some type of vapor barrier sheeting glued to the walls. If that is the case, is there any way for you to gather samples of all of them? Maybe you could gather sample of the soil and put it in a piece of tupperware or bucket. Lay a piece of the liner on top, and some of the adhesive on the liner. If you glued the liner to wood, or liner to cement blocks, and it's possible to do so, replicate those junction(s) in your container also, because there could always be a situation where using ingredients A, B, and C, combining A to B could be fine, and B to C could be fine, but combine A to C and get a reaction. So anyway, seal up your samples for 2-3 days before opening it up, and see if you can reproduce the symptoms.

I think you've almost certainly ruled out mold/mildew, and even general dampness. I really don't think you're describing an animal or critter problem either, because I think you've stated you're all sealed up now. I can't imagine this being related at all to your HVAC system either. So I think you have to at least try to rule out the materials and/or the soil/earth/dirt you're sitting on now. If it's not the materials, the only other option I can think of is that maybe there is something in the soil- i.e., a problem with a soil/sewer line or an maybe old oil-heating tank or oil-heating lines leaching into the soil.
Whether it is a soil-related or a material-related issue, this container test should at least reproduce the odor. Hopefully this will at least lead you to the source....

Odor from Crawl Space

Quote:

Originally Posted by John_W

Gary,

Refresh me:

1. Do you still have crawl air deliberately mixing with indoor air via your HVAC system? I assume not, just checking.

2. What was done to the underside of your floor to stop the smell from getting up into the house? A single coat of a stain blocker won't do the job. If you apply multiple coats, till the surfaces are "as smooth as a baby's bottom" then you will block most smells. At least that's what I had to do to stop a mold smell that was actually on top of my old kitchen floor - before putting new laminate down.

John,

1. I do not have a fresh air intake on my HVAC system.
2. To air seal the crawl, we used expanding foam and caulk to seal all opening around HVAC vents, boots, pvc pipes, cables lines, phone lines, etc. Anywhere there is a hole through the subfloor to the house has been sealed to prevent air leaks. We have not "painted" anything on the joists.

Odor from Crawl Space

I was hoping to at least hear that if the Concrobium didn't work, it would at least settle down the odor enough for you to track it down to a specific area or specific item.

Can you refresh me as to what you have for a floor? Are you on soil or cement? Used a plastic liner for vapor barrier? What kind of adhesives have been used down there?

Reason I'm asking is, I think you said you're on soil floor with some type of vapor barrier sheeting glued to the walls. If that is the case, is there any way for you to gather samples of all of them? Maybe you could gather sample of the soil and put it in a piece of tupperware or bucket. Lay a piece of the liner on top, and some of the adhesive on the liner. If you glued the liner to wood, or liner to cement blocks, and it's possible to do so, replicate those junction(s) in your container also, because there could always be a situation where using ingredients A, B, and C, combining A to B could be fine, and B to C could be fine, but combine A to C and get a reaction. So anyway, seal up your samples for 2-3 days before opening it up, and see if you can reproduce the symptoms.

I think you've almost certainly ruled out mold/mildew, and even general dampness. I really don't think you're describing an animal or critter problem either, because I think you've stated you're all sealed up now. I can't imagine this being related at all to your HVAC system either. So I think you have to at least try to rule out the materials and/or the soil/earth/dirt you're sitting on now. If it's not the materials, the only other option I can think of is that maybe there is something in the soil- i.e., a problem with a soil/sewer line or an maybe old oil-heating tank or oil-heating lines leaching into the soil.
Whether it is a soil-related or a material-related issue, this container test should at least reproduce the odor. Hopefully this will at least lead you to the source....

Pucks,

The floor of the crawl is soil with a 20 mil vapor barrier. We have collected samples of each product prior and were not able to duplicate any smells. I took a sample of the soil under the vapor barrier and it smells simply like dirt, nothin unusual. The one thing I have not done sample wise is to place all the new materials in one container WITH the soil. I had each individually and combined, but not with the soil. I will give that a try.

The v.b. is on the ground and then runs up the walls. There is a foam board insulation on top of the v.b. along the walls. The board insulation is attached with what I call a 2" washer and screw/nail. Along the top of the board insulation is a line of caulk. The ecobatt insualtion previously installed between the floor joist along the outer walls has already been removed. I do not know at this moment if the v.b. was glued to the walls before the board insulation was attached or if the the board insulation holds the plastic in place.

One KEY thing to remember...The soil inside the crawl is the same as before the materials were added. There was not any smell inside the crawl BEFORE the crawlspace was sealed. What I am trying to say is if there was some kind of soil issue before, why did it not smell when I crawled through the crawl with the home inspector? And if, let's say, it were an odor from the soil, would the smell travel throught he v.b?

Odor from Crawl Space

Quote:

Originally Posted by G Ollis

John,

1. I do not have a fresh air intake on my HVAC system.
2. To air seal the crawl, we used expanding foam and caulk to seal all opening around HVAC vents, boots, pvc pipes, cables lines, phone lines, etc. Anywhere there is a hole through the subfloor to the house has been sealed to prevent air leaks. We have not "painted" anything on the joists.

Gary,

At one point, it sounded like you were conditioning the crawl air (via a supply and a return from/to your HVAC system) as part of the sealed crawl space installation. That's different from a fresh air intake.

If the smell is coming from something that was added to your crawl, and its strong enough, it can probably penetrate your sub-floor/floor - through spaces between boards. Any plastic or felt sheeting in the floor won't stop it.

Odor from Crawl Space

Quote:

Originally Posted by G Ollis

Pucks,
One KEY thing to remember...The soil inside the crawl is the same as before the materials were added. There was not any smell inside the crawl BEFORE the crawlspace was sealed. What I am trying to say is if there was some kind of soil issue before, why did it not smell when I crawled through the crawl with the home inspector? And if, let's say, it were an odor from the soil, would the smell travel throught he v.b?

Understood- This is why I'm suggesting, maybe:
A) something used to seal up the crawl is causing the smell, possibly even more than one of those items, such as an adhesive, and another item are reacting together to cause an odor
-or-
B) the soil could still be causing the odor, but when the crawl was "breathing", you never noticed it, while now that it's sealed up the odor has nowhere to go so it is concentrating in the crawl and eventually seeping into the house

So, I was hoping if you combined the items and sealed them in an air-tight container for a few days you would be able to reproduce the odor. The problem I see here is that if it's something in the soil, such as some old oil-burning apparatus, or old soil pipe, it be several inches beneath the surface and/or only in on small area, so if you can't find an area of the crawl as the most concentrated area of odor, it could be really hard to track down a problem in the soil.
If it's a bad enough problem, maybe a better vapor barrier could help (John W. posted previously that the plastic will not stop an odor- I don't know if he's suggesting that the one you used specifically will not stop it or that there is no plastic sheeting that can stop an odor). A more aggressive approach (and much more expensive, so I'd get a few more opinions on it) would be considering a true cement floor, water-proofed and sealed with an odor-blocking primer. You've definitely got a tough issue to crack...

Odor from Crawl Space

I would think if you poured a cement slab underneath your house, it would eliminate the smell. It seems your soil is off-gasing, possibly from a dead animal buried underneath or from prehistoric nature.

Odor from Crawl Space

Quote:

Originally Posted by pucks101

If it's a bad enough problem, maybe a better vapor barrier could help (John W. posted previously that the plastic will not stop an odor- I don't know if he's suggesting that the one you used specifically will not stop it or that there is no plastic sheeting that can stop an odor).

Pucks,

What you suggest about how to think about the source of the smell in the crawl makes good sense to me. I hope Gary finds the source of the smell and is able to stop it, without too much more trouble/expense. That would be the best outcome.

My contribution (if it is one) concerns keeping that smell from getting up into the house proper. I'm thinking that a nasty odor, especially if it has a small molecular size, can probably slip through the felt or whatever is in the floor to prevent drafts, etc - at least enough to makes its offensive presence known.

Odor from Crawl Space

Quote:

Originally Posted by John_W

Pucks,

What you suggest about how to think about the source of the smell in the crawl makes good sense to me. I hope Gary finds the source of the smell and is able to stop it, without too much more trouble/expense. That would be the best outcome.

My contribution (if it is one) concerns keeping that smell from getting up into the house proper. I'm thinking that a nasty odor, especially if it has a small molecular size, can probably slip through the felt or whatever is in the floor to prevent drafts, etc - at least enough to makes its offensive presence known.

I completely agree with you- I was just pointing out that it's possible that there is another type of plastic sheeting, vs. the one he is currently using, that may help. I quoted what you said because I just don't personally know enough about all the available plastics..

Odor from Crawl Space

Quote:

Originally Posted by John_W

Gary,

At one point, it sounded like you were conditioning the crawl air (via a supply and a return from/to your HVAC system) as part of the sealed crawl space installation. That's different from a fresh air intake.

If the smell is coming from something that was added to your crawl, and its strong enough, it can probably penetrate your sub-floor/floor - through spaces between boards. Any plastic or felt sheeting in the floor won't stop it.

John,

The sealed crawl does have conditioned air from the HVAC system normally. Because I am using crawl vents blowing out, I have temporarily closed my trunk line vents into the crawl. I see there is no reason to heat and cool the air that I am currently blowing out of the crawl.

To all,

I posed the soil questions simply as that, a question. I am not familiar enough with vapor barriers to know if a smell from under the barrier could be penetrating the v.b. and seeping through. My problem with the soil idea is I have cut the v.b and smelled under, even took a sample, the soil smells like dirt, nothing more nothing less. The smell does not appear to be coming from the soil. But, I plan on checking it again. And the smell inside my house is a minimum compared to when I started this thread. It is the smell in the crawl that I am attempting to get rid of because my ultimate goal is to have it gone.

Odor from Crawl Space

Gary, I am having the same issue. It sounds like you have done an excellent job of sealing the crawlspace. I would appreciate another update from you.

I encapsulated my 1,300 sq. ft. crawl a few months ago, including eliminating the foundation wall vents and installing a supply and a return vent in the HVAC to condition that air. The cat pee smell started slowly, then got worse and worse.

BTW - my crawl humidity has hovered around 68%.

I talked to Larry at Crawlspace Concepts, a supplier of liners, etc. A very knowledgeable guy. He said the cat piss smell is usually soil gas. I don't understand exactly how it happens after the liner is installed. He did suggest slitting the liner in a place or two and sticking my nose down there and taking a whiff to verify. (Gary, I know you did this and didn't smell anything other than dirt).

Larry suggested installing a soil gas mitigation system. The idea is to pull the gases under the liner, out of the house. You use 4" perforated drain pipe and a radon mitigation fan. The idea is, you slit the liner and slide some of these lengths of perforated pipe under the liner. He said you don't even have to glue them them, it's okay to just butt them together. The stuff is fairly cheap.

Create some sort of array, perhaps along the walls. Connect the radon fan and duct it all up and out of the house. Through the roof might be the best. Larry is in the process of sketching up the array for me and we will probably be doing this installation within the month. We may also be purchasing a crawlspace dehumidifier.

I'm attaching Larry's sketch of my crawlspace, and his recommendation for the layout of the perforated drain tubing. Not quite sure yet where I am going to connect the radon fan into it.

One other thing that may have been a factor. We noticed the evaporator coil in the heat pump air handler was not channeling the all condensation and it some would drain out onto the garage floor. The interior of the air handles is lined with fiberglass, so I thought perhaps mold was building up there. Lots of side issues here, but the bottom line is it's a lousy air handler design. (20+ y.o.).

One person on the HVAC section of this site suggested cleaning the evaporator coils to eliminate the dripping. Well, they looked just fine, but I bought a can of foaming coil cleaner from our local HVAC distributor. Sprayed it on, and didn't think it would work. Well, it's still dripping, but suddenly the smell is reduced. Maybe there was mold build-up on the coils, though I sure couldn't see anything. Go figure, but if I stick my head in the crawl, I still smell the cat pee.

So, the first thing on our list is to do the soil gas remediation. If that doesn't work, we will install a good crawlspace dehumidifier (may do that anyway).